Cooling tube and method of manufacture thereof

ABSTRACT

An injection-molded plastic part cooling tube has an extruded cylindrically shaped tube with an inside surface and an outside surface. An extruded cooling channel is disposed inside the cylindrically shaped tube, between the inside surface and the outside surface. A method for forming an injection-molded-plastic-part cooling tube includes the step of extruding a hollow aluminum tube having an inside surface, an outside surface, and at least one cooling channel in the hollow aluminum tube between the inside surface and the outside surface. Alternative cooling tubes include a tubular porous insert for vacuum forming molded articles.

[0001] This is a continuation-in-part application of co-pendingapplication Ser. No. 10/246,916, filed Sep. 19, 2002, the contents ofwhich are therefore incorporated herein by reference.

BACKGROUND OF INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates, in general, to cooling tubes andis particularly, but not exclusively, applicable to cooling tubes usedin conjunction with a plastic injection-molding machine to cool plasticparts, such as plastic parisons or preforms. More particularly, thepresent invention relates to a structural configuration of these coolingtubes, and also to methods of manufacturing and using such tubes, forexample in the context of a manufacturing process for preforms made frompolyethylenetetraphthlate (PET) or the like.

[0004] 2. Summary of the Prior Art

[0005] In the injection molding art, it is known to use post moldcooling systems that operate simultaneously with the injection moldingcycle. More specifically, while one injection cycle is taking place, thepost mold cooling system, typically acting in a complementary fashionwith a robotic part removal device, is operative on an earlier formedset of molded articles that have been removed from the mold at a pointwhere they are still relatively hot, but sufficiently solid to allowlimited handling.

[0006] Further, it is known to use fluid-cooled, cooling tubes forpost-mold temperature conditioning of molded plastic parts, such asplastic parisons or preforms. Typically, such tubes are made fromaluminum (or other materials having good thermal conductivity), and areformed by conventional machining methods from solid stock.

[0007] For example, each of U.S. Pat. Nos. 4,102,626 and 4,729,732disclose a cooling tube formed with an external cooling channel machinedin the outer surface of the tube body. A sleeve is then attached to thebody to enclose the channel and provide an enclosed sealed path for theliquid coolant to circulate around the body.

[0008] WO 97/39874 shows a tempering mold that has circular coolingchannels included in its body.

[0009] EP-A-0700770 discloses another cooling tube configuration forholding and cooling a preform that includes an elastically deformableholder with internal cooling passages, the holder operable between anopen position and a holding position by exerting external force.Suggested embodiments include the internal cooling passages oriented ineither a helical or longitudinal direction. No suggestion as to a methodof manufacturing the holder or a specific construction (e.g. material)is given.

[0010] A problem with known cooling tubes is that they are expensive andare time-consuming to make and assemble. Further, the operational mass(i.e. including cooling water) of the cooling tube is of particularconcern considering that a typical robot take-out system may include oneor more sets of cooling tubes in an array, and therefore the cummulativemass supported by the robot quickly becomes a significant operatingand/or design consideration (i.e. inertia or momentum considerations forthe robot). Moreover, the robot typically operates to remove many tensof preforms in a single cycle (with present PET systems producing up toone hundred and forty-four preforms per injection cycle) so the energyexpended by the robot and the technical specification of the robot areunfortunately relatively high. The provision and operation of a highspecification robot therefore impose considerable financial costpenalties on an end user.

[0011] U.S. Pat. No. 5,870,921 discloses an extrusion die for use inproducing aluminum alloy articles of extruded shapes or tube having avoid with defined internal dimension.

SUMMARY OF INVENTION

[0012] According to a first aspect of the present invention, structureand/or steps are provided for an injection-molded plastic part coolingtube that is extruded to define a cylindrically-shaped tube with aninside surface, an outside surface, and at least one cooling channel.

[0013] According to a second aspect of the present invention, injectionmolding machine structure and/or steps are provided with a moldstructure which molds a plurality of plastic parts. A plurality ofextruded cooling cavities provided and configured to hold and cool theplurality of plastic parts after they are molded by the mold structure.Each cooling cavity including a plurality of cooling channels defined bythe extrusion and configured to provide for a coolant flow through theplurality of cooling cavities to extract heat from the plurality ofplastic parts while they are held by the plurality of cooling cavities.

[0014] According to a third aspect of the present invention, a methodfor extruding an injection-molded-plastic-part cooling tube includes thesteps of extruding a hollow aluminum tube having an inside surface, anoutside surface, and at least one cooling channel.

[0015] According to a fourth aspect of the present invention, a tubeassembly includes a tubular porous insert for vacuum forming a moldedarticle, and to improve cooling efficiency. The porous insert includesan inner surface that is contoured to substantially correspond with thefinal desired molding surface of the molded article. Pressure channelsin the porous insert provide a conduit for establishing a region ofrelatively low vacuum pressure and for evacuating air through the porousstructure of the porous insert, thereby drawing a deformable moldedarticle into contact with the contoured inside surface.

[0016] In its preferred embodiment, the present invention advantageouslyprovides an extruded cooling tube that is easily manufactured and whichis of a lightweight construction that, beneficially, reduces robotspecification requirements and/or improves robot cycle time. Futhermore,the cooling tube has enhanced cooling capabilities as a consequence ofimproved and integrally formed channeling. In addition, alternativeembodiments of the present invention provide tube assemblies that arecapable of vacuum forming a molded article.

BRIEF DESCRIPTION OF DRAWINGS

[0017] Exemplary embodiments of the present invention will now bedescribed with reference to the accompanying drawings, in which:

[0018]FIG. 1 is a plan view of a typical injection molding machineincluding a robot and an end-of-arm tool;

[0019]FIG. 2 is a sectional view of a cooling tube according to apreferred embodiment of the present invention;

[0020]FIG. 3 is a view along section ‘A-A’ of FIG. 2 cooling tube;

[0021]FIG. 4 is an isometric view of a cooling tube porous insert; and

[0022]FIG. 5 is a sectional view of a cooling tube according to analternative embodiment of the invention.

DETAILED DESCRIPTION

[0023] The present invention will now be described with respect toembodiments in which an extruded cooling tube is used in a plasticinjection molding machine, although the present invention is equallyapplicable to any technology in which, following part formation, coolingof that part is undertaken by a cooling tube or the like. For example,the present invention can find application in a part transfer mechanismfrom an injection molding machine and a blow-molding machine.

[0024]FIG. 1 shows a typical injection molding machine 10 capable ofco-operating with a device supporting the cooling tube of the presentinvention. During each injection cycle, the molding machine 10 producesa number of plastic preforms (or parisons) 32 corresponding to thenumber of mold cavities defined by complementary mold halves 12, 14located within the machine 10.

[0025] The injection-molding machine 10 includes, without specificlimitation, molding structure such as a fixed platen 16 and a movableplaten 18. In operation, the movable platen 18 is moved relative to thefixed platen 16 by means of stroke cylinders (not shown) or the like.Clamp force is developed in the machine, as will readily be appreciated,through the use of tie bars 20, 22 and a machine clamping mechanism 100that typically generates a mold clamp force (i.e. closure tonnage). Themold halves 12, 14 together constitute a mold generally having one ormore mold cavities 22, 24, with the mold halves 12, 14 each located inone of the movable platen 18 and the fixed platen 16. A robot 26 isprovided, adjacent the fixed platen 16 and the movable platen 18, tocarry a carrier plate assembly 11, such as a take-out plate 28 thatcontains a number of preform cooling tubes 30 at least corresponding innumber to the number of preforms 32 produced in each injection cycle,and may be a multiple thereof.

[0026] In use, in a mold open position (as shown in FIG. 1), the robot26 moves the carrier plate assembly 11 into alignment with, typically, acore side of the mold and then waits until molded articles (e.g.preforms 32) are stripped from respective cores 21, 23 into respectivelyaligned cooling tubes 30 by operation of a stripper plate 33, or thelike.

[0027] Cooling tubes 30 generally include an internal surface shaped tocorrespond to the external profile of the molded article (e.g. preform32), so in the context of a PET preform the cooling tubes 30 arepreferably cylindrically-shaped hollow tubes with an open end throughwhich passes a preform 32. Each cooling tube 30 further including apressure channel at the base thereof connected to a vacuum or suctionunit 34, operational to draw and/or simply hold a preform 32.

[0028] Generally, the carrier plate assembly 11 will be cooled either byconnection to a suitable thermal sink and/or by a combination oftechniques, including internal water channels.

[0029]FIG. 2 shows a sectional view through a cooling tube 350 of anembodiment of the present invention. The cooling tube 350 preferablycomprises an extruded one-piece tube 352 with an outside surface 384, aninside surface 382 for operating on the preform 32. The cooling tube 350includes a cooling circuit for cooling inside surface 382 that includeslongitudinally oriented cooling channels 354 formed by extrusion betweenthe inside surface 382 and the outside surface 384 of the tube 352. Thecooling channels 354 are connected together in a desired flowconfiguration by any number of connecting channels 356, and the coolingcircuit connected to a source and sink of coolant through inlet andoutlet channels 390 and 392. The connecting channels 356 are located atthe top and base of tube 352, between the outside surface 384 and theinside surface 382, and extend between two or more cooling channels 354.The connecting channels 356 are closed on one side by sealing rings 358.The sealing rings 358, including seals 359, are retained in a groove atthe top and base of the cooling tube 350 by snap rings 366 or otherknown fastening means. The cooling tube 350 further includes a centralplug 364 inserted into its base and retained by shoulder 367, thecentral plug 364 including a contoured inside surface 303 for supportingand otherwise operating on the bottom of a preform 32. The central plug364 also includes a pressure channel 394, for connection to a vacuumsource, for the purpose of assisting in the transfer of a preform 32into the cooling tube 350. The coolant inlet and outlet channels 390 and392 of the cooling circuit being provided in the central plug 364.

[0030] The tube 352 preferably comprises a one-piece extruded tube withlongitudinal cooling channels 354 that may have a cross sectionalprofile selected from a wide range of shapes. Using conventionalmachining techniques (e.g. milling) to machine the channels 354 with theshape shown in FIG. 3 is generally not practical beyond a length ofabout 4 times the diameter of the cutter being used, thereby limitingthe length of cooling tube made by this method to an unsuitably smallrange. Therefore, an extruded tube can be identified as one having anintegral cooling channel having a length generally greater than fourtimes the minor diameter of the cooling channel 354, or one as having asubstantially constant non-cylindrical cooling channel 354 shape.

[0031] The cooling channels 354 formed in the extrusion process provideschannels for cooling fluid to circulate in the tube, extracting heatfrom the preform 32 through the tube inside surface 382. The coolingtube may include four cooling channels 354 (as shown in FIG. 3). Theshapes of channels 354 are preferably arcuate-shaped, elongated slotsthat present a larger cooling surface area than drilled holes.Preferably, the cumulative angular extent of all elongated slots isgreater than 180 degrees, the angular extent of each elongated slotbeing the measure of the contained, angle of an arc concentric with thecooling tube with its terminus points defining a maximum arc lengththrough the elongated slot. Such a shape works to optimize thermaltransfer from a preform 32 due to the coolant distribution that extendsaround a substantial portion of, and in proximity to, the inside surface382 that contacts the preform 32, and also due from the high volume flowrate of coolant supported by the large cross sectional profile of thecoolant channel 53. Further, the preferred coolant channel 354cross-sectional profile provides for a relatively lightweight coolingtube 350, that results in an overall mass reduction in the carrier plateassembly 11 that may be considerable given that some carrier plateassemblies include upwards of 432 tubes (i.e. a carrier plate assemblywith 3 sets of 144 cooling tubes), thereby allowing a lighter duty andhence lower cost robot to be used and/or allowing the plate to movefaster thereby saving some cycle time and reducing energy consumption.

[0032] In an alternative embodiment of the invention, the four arcuateshape channels shown in FIG. 3 could be changed to only two largerarcuate shapes (not shown) so that one channel represents the input andthe other the output, thereby simplifying the connecting channels 356.

[0033] The central plug 364 preferably includes a contoured insidesurface 303 shaped to substantially match that of the part being cooled.The central plug 364 is preferably made from aluminum, and functions tocool the gate area of the preform, to define a channel for the vacuum,and to facilitate the coupling of the cooling channels to the carrierplate 11, where necessary. Provision for the pressure channel 394 ispreferably at the plug's center. In one embodiment, the central plug 364is retained between the shoulder 367 of the cooling tube and thetake-out plate 28. A tube fastener 368, such as a screw or bolt, isprovided to couple the cooling tube 350 to the take-out plate 28.Alternate means of assembling the plug 14 and fastening the cooling tube350 to the take-out plate 28 may be used.

[0034] Exemplary physical dimensions of a cooling tube 350 for anarbitrary preform 32 according to the present invention suggest arepresentative length of about 100 mm long, an interior diameter ofabout 25 mm, and outer diameter of about 41 mm. For such an arbitrarycooling tube, the cooling channels 354 are preferably about 1-4 mm inthickness, about 80 mm in circumference, and about 100 mm (preferablythe same length as tube) in axial length. Of course, tubes of differentdiameters and lengths would be made to suit the geometry of any preform32, and hence wide variations in the coolant channel 354 dimensions arepossible. The cooling tube 350 is preferably made from Aluminium.

[0035] According to the present invention, an extruding process is usedto form a tube 352 including the cooling channels and a hole, the holepreferably sized to be smaller than any of the plastic parts destinedfor cooling in the tube. The extrusion process is consistent with knowntechniques. The tube 352 is then cut to length and the molding surfaceand any other desired features (such as connecting channels 356, sealingring 358 grooves, and any coolant inlet/outlet or pressure channels,coupling structure, etc.) are then machined. The central plug 364 isthen machined, including adding desired features (such as coolant 390,392 and pressure channel 394). The central plug 364 with all necessaryseals is then installed into the cooling tube 350, and the sealing rings358 with seals 359 installed into the sealing ring grooves in the topand bottom of the cooling tube 350, so that the entire assembly is readyfor installation onto the take-out plate 28.

[0036] In a preferred embodiment, the connecting channels 356 at the topend of the tube 352 may be provided by machining through alternateseparation walls (not shown) of the cooling channel 354. At the take-outplate 28 (bottom) end of the tube 352, similar alternate separationwalls (not shown) are machined to connect the cooling channels 354 andprovide connections to the cooling fluid inlet channel 390 and thecooling fluid outlet channel 392. Alternately, the cooling channels 354in the tube wall could be connected directly to the corresponding portsin the take-out plate 28.

[0037] In an alternative embodiment of the present invention (not shown)the cooling tube is extruded to define a cylindrically-shaped tube withan inside surface, an outside surface, and at least one cooling channel354 formed on the outer surface of the tube 352. A tubular sleevefits-around the tube 352 thereby enclosing the cooling channels 354.Seals are provided between the tube 352 and sleeve to provide awater-tight connection. The cooling channels may be connected aspreviously described in the preferred embodiment of the invention.

[0038] In an alternative embodiment of the present invention (not shown)the cooling tube is extruded to define a cylindrically-shaped tube withan inside surface, an outside surface, and at least one cooling channel354 formed on the outer surface of a tubular sleeve that fits-around thetube 352 thereby enclosing the cooling channels 354. Seals are providedbetween the tube 352 and sleeve to provide a water-tight connection. Thecooling channels may be connected as previously described in thepreferred embodiment of the invention.

[0039] In operation, the cooling tube is used similarly to thatdescribed in U.S. Pat. No. 4,729,732. It is preferred that the internaldimensions of the cooling tube are slightly smaller than the externaldimensions of the preform being cooled. Thus, as the preform shrinks,its external size is reduced, and a vacuum acting through the centralplug draws the part further into the cooling tube so that an intimatefit or contact of the preform's external surface is maintained with theinside surface of the cooling tube. Alternately, the internal dimensionsof the cooling tube can be manufactured to be the same size or slightlylarger than the external size of the preform being cooled, so as topermit a flow of air to be drawn past the part's external surfaces bythe vacuum.

[0040] In more detail, after the preforms are formed in the injectionmolding machine, the mold opens by stroking the movable platen 18 awayfrom the fixed platen 16, and the robot arm (carrying the carrier plateassembly 11) moves between the mold halves 12 and 14 so that the coolingtubes 50 can receive a set of preforms 32 that are ejected from cores23. Applied suction may be used to encourage transfer of the preforms 32from the cores 23 to the cooling tubes 350, and/or to retain thepreforms therein. The carrier plate assembly 11 is then moved out frombetween the mold halves 12, 14, and then orientated so that the carrierplate assembly 11 is sequentially or selectively placed adjacent to acooling station, a receiving station, or a conveyor. The preforms maythen be transferred thereto.

[0041] In addition to the improved cooling performance of the coolingtube, there is a substantial benefit in reduced cost of manufacture. Anextruded cooling tube according to the present invention, can benefitfrom a cost reduction relative to conventionally manufactured tube dueto substantially reduced machining requirements.

[0042] In an alternative embodiment of the invention (not shown) thetube assembly 350 of FIG. 2 may be modified to include a tubular porousinsert 452, as shown in FIG. 4, along the inside surface 382 for vacuumforming a preform 32 and to improve preform 32 cooling efficiency due toa better heat conduction interface (i.e. larger surface area contact andmore intimate fit). Reference is therefore now made to co-pendingapplication Ser. No. 10/246,916, filed Sep. 19, 2002, and entitled“Cooling Tube With Porous Insert”. The porous insert 452 includes aninner surface 482 and outer surface 483, the inner surface 482 contouredto correspond substantially with the final desired molding surface ofthe preform 32, the outer surface 483 may be segmented by a set oflongitudinally directed pressure channels 466. The pressure channels 466provide a conduit for establishing a region of very low vacuum pressurein proximity to the portion of the porous insert 452 between the insidesurface 482 and the outside surface 483 and thereby to evacuate airthrough the porous structure of the porous insert 450 for the purpose ofdrawing a deformable preform 32 into contact with the contoured insidesurface 482 of the porous insert 452, thereby vacuum forming the preform32. The porous insert 452 is preferably made from a highly thermallyconductive material, such as aluminum. The material selection for theporous insert further characterized by the requirement for a porousstructure with a porosity preferably in the range of about 3-20 microns.Further, the porous insert 452 may be advantageously manufactured in aprocess that includes the step of extrusion.

[0043] Yet another alternative embodiment of the invention is shown inFIG. 5, wherein a tube assembly 450 for vacuum forming a preform 32 isprovided. The tube assembly 450 includes a tube 454 that may be machinedfrom available tube stock, however an extruded tube such as tube 352 (asexemplified in FIG. 2) may also be used. The tube 454 includes an insertbore 455 for receiving a porous insert 452, as exemplified in FIG. 4.The porous insert 452 is retained in the tube 454 by a central plug 464,the central plug 464 received in a first and second plug bore 457, 458of the tube 454. The central plug 464 is further retained in the tube454 by its shoulder 467 bearing against the step between the first andsecond plug bore 457, 458. The shoulder 467 on the central plug 464corresponds to a step in the diameter of the central plug 464 with anarrowed portion at its upper end that provides an annular channel 465between the central plug 464 and the second plug bore 458 of the tube454. The annular channel 465 connects the pressure channels 466 ofporous insert 452 with a channel 420 that is formed in the central plug464 that is in turn connected in use to a first vacuum channel intake-out plate 28. The central plug 464 includes a contoured insidesurface 403 that substantially corresponds to the dome portion ofpreform 32 that may be used for forming and cooling the region. Thecentral plug 464 further includes inlet and an outlet coolant channel490, 492, and a pressure channel 494, for connection to coolant inletand outlet channels 116, 118 and a second pressure channel in thetake-out plate 28 respectively. The inlet and outlet channels 490, 492of the central plug 464 are further connected to a cooling groove 493formed on the outer surface of the tube 454 thereby forming a coolingcircuit. The tube assembly 454 further includes a sleeve 456 that isretained on the outer surface of the tube 454. Seals 459 are alsoprovided between the sleeve 456 and tube 454, and between the centralplug 464 and the tube 454 to provide air and water tight connectionsbetween components forming the tube assembly 450. The tube 454 furtherincludes a groove at its open and for receiving an end seal 404 thatprovides in use an airtight seal between the preform support ledge 100and the tube assembly 450 for enclosing the volume formed between thepreform 32 and tube assembly 450, thereby enabling the development ofthe required low vacuum forming pressure. The primary components of thetube assembly 450 are preferably made from a highly thermally conductivematerial, such as aluminum. The operation of the tube assembly 454installed on the take-out plate 28 of the carrier plate assembly 11 willnow be described. The take-out plate 28 provides cooling fluid inlet andoutlet channels and first and second vacuum channels to correspond withthe ports on the central plug 464. In use, a preform 32 is drawn intothe tube assembly 450 by a relatively high flow rate suction actingthrough the pressure channel 494 that further retains the preform 32once the preform support ledge 100 is sealed against the end seal 404thereby stopping air flow. A high vacuum is then applied through thevacuum channel 420 in the central plug 464, then through the annularchannel 465 and pressure channels 466, whereupon the vacuum acts throughthe porous wall of the porous insert 452. The volume of air between thepreform 32 and the inner surface 482 of the porous insert 452 is atleast partially evacuated to cause the drawing of the preform outersurface into contact with the porous insert 452. Once in contact withthe porous insert 452, the preform 32 is cooled by conduction, its heatmoving through a path from the preform outer surface to the porousinsert 452, to the tube 454, and to the circulating coolant. Once enoughheat has been removed from the preform 32 to ensure that it will retainits shape, the high vacuum acting through the vacuum channels 466 isreleased and a positive pressure is applied through the pressure channel494 to assist in the ejection of the preform 32.

[0044] Thus, what has been described is an extruded cooling tube for aplastic part, a porous insert for use with a tube assembly for vacuumforming preforms, various advantageous embodiments of tube assemblies,methods of making the afore mentioned, and a method of using a tubeassembly, which will greatly reduce the cost of such tubes in injectionmolding and/or improve the quality of the molded preform 32.

[0045] All U.S. and foreign patent documents discussed above are herebyincorporated by reference into the Detailed Description of the PreferredEmbodiment.

[0046] While the present invention has been described with respect towhat is presently considered to be the preferred embodiments, it is tobe understood that the invention is not limited to the disclosedembodiments. To the contrary, the invention is intended to cover variousmodifications and equivalent arrangements included within the scope ofthe appended claims. The scope of the following claims is to be accordedthe broadest interpretation so as to encompass all such modificationsand equivalent structures and functions. For example, while the tubeassembly of the present invention has been described in the context of aplastic injection molding machine, it will be appreciated that it isequally applicable to any technology in which, following part formation,cooling of that part is undertaken by a cooling tube or the like, e.g.in a part transfer mechanism between an injection molding machine and ablow-molding machine.

What is claimed is:
 1. An injection-molded plastic part cooling tubeapparatus, comprising: an extruded tube having an inside surface and anoutside surface; and at least one cooling channel produced by extrusion.2. The apparatus according to claim 1, wherein said cooling channel isdisposed between said inside surface and said outside surface.
 3. Theapparatus according to claim 1, further comprising a sleeve cooperatingwith said tube to enclose said cooling channel, said tube being disposedinside of and adjacent said sleeve, and wherein said cooling channel isdisposed on one of either: (i) said outside surface of said tube; (ii)an inside surface of said sleeve.
 4. The apparatus according to claim 2,wherein said cooling channel has a substantially constant profile, whichextends in a longitudinal direction of said tube.
 5. The apparatusaccording to claim 4, wherein said cooling channel has a length which isat least about four times a minor diameter of said cooling channel ofsaid tube.
 6. The apparatus according to claim 5, wherein said tube hasa cross-section comprising a plurality of said cooling channels asarcuate, elongated slots.
 7. The apparatus according to claim 6, whereinthe cumulative angular extent of all elongated slots is greater than 180degrees.
 8. The apparatus according to claim 5, wherein said elongatedslots are coupled together to form at least one cooling circuit aroundsaid tube.
 9. The apparatus according to claim 1, wherein said tubecomprises an extrudable metal.
 10. The apparatus according to claim 9,wherein said tube comprises extruded aluminum.
 11. The apparatusaccording to claim 1, further comprising a plug disposed in a distal endof said tube and configured to contact a distal end of theinjection-molded plastic part.
 12. The apparatus according to claim 11,wherein said plug comprises aluminum, and includes a cooling channelinlet, a cooling channel outlet, and at least one pressure channel, saidcooling channel inlet, said cooling channel outlet, and said pressurechannel each being configured to communicate with a respective take-outplate cooling channel inlet, cooling channel outlet, and pressurechannel.
 13. The apparatus according to claim 11, wherein said plug hasa dome-shaped internal surface configured to, contact and cool acorresponding dome-shaped end of an injection molded plastic part insidesaid cooling tube.
 14. The apparatus according to claim 1, furthercomprising an injection-molded plastic part sealing structure disposedat a distal end of said cooling tube.
 15. The apparatus according toclaim 11, further comprising a porous insert with at least one pressurechannel and a contoured inside surface.
 16. An injection moldingmachine, comprising: mold structure that molds a plurality of plasticparts; a plurality of extruded cooling cavity structures configured tohold and cool the plurality of plastic parts after they are molded bysaid mold structure, said cooling cavity structures each having aninside surface, an outside surface, and at least one cooling channelproduced by extrusion and providing for a coolant flow to extract heatfrom the plurality of plastic parts while said parts are held by theplurality of extruded cooling cavity structures.
 17. The injectionmolding machine according to claim 16, wherein said at least one coolingchannel is disposed between said inside surface and said outsidesurface.
 18. The injection molding machine according to claim 16,further comprising a sleeve cooperating with said cooling cavitystructure to enclose said cooling channel, said cooling cavity structurebeing disposed inside of and adjacent said sleeve, and wherein saidcooling channel is disposed on one of either: (i.) said outside surfaceof said cooling cavity structure; (ii) an inside surface of said sleeve.19. The injection molding machine according to claim 17, wherein said atleast one cooling channel has a substantially constant profile, whichextends in a longitudinal direction of each respective said coolingcavity structure.
 20. The injection molding machine according to claim19, wherein said at least one cooling channel has a length which is atleast about four times a minor diameter of said at least one coolingchannel.
 21. The injection molding machine according to claim 20,wherein each said cooling cavity structure has a cross-sectioncomprising a plurality of cooling channels as arcuate, elongated slots.22. The injection molding machine according to claim 21, wherein thecumulative angular extent of all elongated slots is greater than 180degrees.
 23. The injection molding machine according to claim 20,wherein said elongated slots are coupled together to form at least onecooling circuit around each said cooling cavity structure.
 24. Theinjection molding machine according to claim 16, wherein said coolingcavity structure comprises an extrudable metal.
 25. The injectionmolding machine according to claim 24, wherein said cooling cavitystructure comprises extruded aluminum.
 26. The injection molding machineaccording to claim 16, further comprising a plug disposed in a distalend of each of said cooling cavity structure and configured to contact adistal end of the injection-molded plastic part.
 27. The injectionmolding machine according to claim 26, wherein said plug comprisesaluminum, and includes a cooling channel inlet, a cooling channeloutlet, and at least one pressure channel, said cooling channel inlet,said cooling channel outlet, and said pressure channel each beingconfigured to communicate with a respective take-out plate coolingchannel inlet, cooling channel outlet, and pressure channel.
 28. Theinjection molding machine according to claim 26, wherein said plug has adome-shaped internal surface configured to contact and cool acorresponding shaped end of an injection-molded plastic part inside eachsaid cooling cavity structure.
 29. The injection molding machineaccording to claim 26, further comprising a porous insert with at leastone pressure channel and a contoured inside surf ace.
 30. The injectionmolding machine according to claim 16, further comprising aninjection-molded plastic part sealing structure disposed at a distal endof each of said cooling cavity structure.
 31. A method for forming aninjection-molded-plastic-part cooling tube, comprising the steps of:extruding a hollow aluminum tube having an inside surface and an outsidesurface and at least one cooling channel.
 32. The method according toclaim 31, wherein said step of extruding said tube includes extrudingsaid at least one channel between said inside surface and said outsidesurface.
 33. The method according to claim 31, wherein said step ofextruding said tube includes extruding said at least one channeldisposed on said outside surf ace of said tube.
 34. The method accordingto claim 31, wherein said extruding steps are performed with aluminum.35. The method according to claim 31, wherein the step of extruding saidtube comprises the step of extruding said at least one channel so that across-section of the cooling tube includes a plurality of said coolingchannels as arcuate, elongated slots substantially surrounding saidinside diameter.
 36. The method according to claim 31, wherein said atleast one channel comprises a plurality of cooling channels and furthercomprising the step of machining a connecting channel configurationbetween said cooling channels to complete a cooling circuit around saidcooling tube.
 37. The method according to claim 36, further comprisingthe step of forming a central plug including cooling fluid channels andat least one air vacuum channel.
 38. The method according to claim 37,further comprising the step of placing a plug in one end of said hollowtube, to form a closed end of the cooling tube.
 39. The method accordingto claim 37, further comprising the step of forming a porous insert withat least one pressure channel and a contoured inside surface.
 40. Themethod according to claim 39, further comprising the step of insertingsaid porous insert into said hollow tube and retaining said insert insaid tube by inserting said plug.
 41. The method according to claim 39,wherein said porous insert is manufactured by a process that includesextrusion.
 42. A cooling tube apparatus for vacuum forming of aninjection-molded plastic preform, comprising: a tube that includes aninsert bore for receiving a porous insert, at least one plug bore forreceiving and retaining a central plug, a cooling groove formed on theouter surface of the tube, and a groove at its open end for receiving anend seal, in use, the end seal works to seal a portion of said preformwithin said tube and thereby forms a closed volume between said preformand said tube; and a sleeve that fits-around said outer surface of saidtube and sealed thereto for enclosing said groove; a central plug thatincludes a contoured inside surface to substantially correspond with adome portion of said preform, an inlet and an outlet coolant channel forconnection with said groove of said tube, a pressure channel thatassists in receiving and ejecting said preform, and a vacuum channelthat connects to an annular channel formed between a narrowed portion atan upper end of said plug and said plug bore of said tube; and a porousinsert that includes an inner surface contoured to substantiallycorrespond with a final desired molding surface of the preform, an outersurface, and at least one longitudinally directed pressure channelconnected to said annular channel, whereby in use, the pressure channelsprovide a conduit for evacuating air through the porous insert for thepurpose of drawing a deformable preform into contact with said contouredinside surface thereby vacuum forming said preform.
 43. The cooling tubeaccording to claim 42, wherein said tube, said porous insert, said plug,and said sleeve are preferably made from a highly thermally conductivemetal.
 44. The cooling tube according to claim 43, wherein said porousinsert is preferably made from a porous material with a porosity in therange of about 3-20 microns.
 45. The cooling tube according to claim 44,wherein said porous insert material is a porous aluminum.